The present invention relates to 3-substituted-4-hydroxy- and 4-acetoxystyrene compounds and more particularly to 3,5-disubstituted-4-acetoxystyrene wherein the 3,5-substitution is independently C.sub.1 to C.sub.10 alkyl or alkoxy, amino, such as primary or secondary amino or halo, and a process for its preparation. In its most preferred form, the invention relates to 3-mono- and 3,5-dihalogenated 4-acetoxystyrenes which contain chlorine or bromine as the halogen, and a method of preparation thereof.
3,5-dibromo-4-hydroxystyrene compounds have been known for a long time and were initially prepared from 4-hydroxycinnamic acid by
a) bromination of positions 3 and 5 on the ring as well as addition of bromine to the double bond.
b) dehydrobromination with concurrent decarboxylation, leading to reconstitution of the vinylic double bond.
c) then, addition of hydrogen bromide to said double bond to form a saturated vicinal dibromide,
d) finally, by debromination for reconstruction of the vinylic double bond (see Liebigs Annalen der Chemie, 322, 235 (1902)) as shown in the following scheme: ##STR1##
It is known in the art to produce monomers, homopolymers and copolymers of unsubstituted 4-acetoxystyrene and to hydrolyze the same to produce 4-hydroxystyrene derivatives or polyvinyl phenols. Such find use in the production of photoresists, adhesives, coating compositions, and the like. In particular, polymers or copolymers prepared from non-halogenated monomers are used for preparing coating compositions and as binders for photoresists. In this connection, reference is made to post-brominated poly(4-hydroxy)styrenes which are used in accordance with German patent application P 37 30 784.3 as radiation-sensitive compounds in corresponding photoresists. The compounds of this invention find use as intermediates in the production of such polymers as poly(3,5-dimethyl-4-acetoxystyrene) and poly(3,5-dimethyl-4-hydroxystyrene). These later compounds are useful as improved binder resins for photoresists which have a more advantageous dissolution rate in commercially accepted photoresist developers, and are more fully described in U.S. patent application Ser. No. 07/097815 filed on even date herewith and incorporated herein by reference, now abandoned. Alpha acetoxystyrene and beta acetoxystyrenes are described in U.S. Pat. No. 4,144,063 and acetoxymethylstyrene is taught in U.S. Pat. No. 3,963,495. U.S. Pat. No. 4,075,237 describes 1,4-dimethyl-2-hydroxystyrene, while U.S. Pat. No. 4,565,846 teaches the use of poly(3,5-dimethyl-4-hydroxystyrene). Japanese patent 84023747 describes anti-static compounds employing poly-acetoxymethylstyrene and U.S. Pat. No. 4,221,700 describes a stabilized synthetic polymer composition using poly(alkylated alkenylphenol) including 2-methyl paravinyl phenol. U.S. Pat. Nos.4,600,683 and 4,543,397 describe poly (alphamethyl vinylphenol). U.S. Pat. Nos. 4,517,028; 4,460,770 and 4,539,051 describe dimethyl vinyl phenol.